Router symbol: Router, by Jeremy Grossmann, created for GNS-3.
Original source (unmodified asset): https://github.com/GNS3/gns3-gui/blob/master/resources/symbols/router.svg
The embedded metadata identifies GPL version 2: http://creativecommons.org/licenses/GPL/2.0/
The complete asset source is provided in gns3-router.svg and the GPL-2.0 license text is included alongside it.
The topology SVGs using this symbol are distributed under GPL-2.0 with their editable SVG source provided.